In the field of digital logic, extensive use is made of well known and highly developed complimentary metal-oxide semiconductor (CMOS) technology. As CMOS has begun to approach maturity as a technology, there is an interest in alternatives that may lead to higher performance in terms of speed, power dissipation computational density, interconnect bandwidth, and the like. An alternative to CMOS technology comprises superconductor based single flux quantum circuitry, utilizing superconducting Josephson junctions (JJs), with typical signal power of around 4 nanowatts (nW), at a typical data rate of 20 gigabits per second (Gb/s) or greater, and operating temperatures of around 4 kelvins.
A majority gate is a logical gate that returns true if and only if more than 50% of its inputs are true. Phase-mode logic allows digital values to be encoded as superconducting phases of one or more JJs. For example, a logical “1” may be encoded as a high phase and a logical “0” may be encoded as a low phase. For example, the phases may be encoded as being zero (meaning, e.g., logical “0”) or 2π (meaning, e.g., logical “1”). These values persist across RQL clock cycles because there is no requirement for a reciprocal pulse to reset the JJ phase.